1. Field of the Invention
The present invention relates to a liquid crystal display device, and more particularly, to a technology of horizontally dividing a screen into a plurality of display regions and vertically scanning those display regions in a parallel manner.
2. Description of the Related Art
Liquid crystal display devices are used in products such as a flat panel television set, a personal computer, a tablet terminal, and a smartphone. Particularly in the application of a large-sized panel represented by the flat panel television set, there are demands for increase in number of pixels such as 4K resolution (4K2K) and higher frame rate driving such as dual speed and quad speed, for image display in higher resolution, three-dimensional display, and improvement in moving image quality. Those demands require shorter data writing time to be allocated for each horizontal scanning line during vertical scanning of a screen, and hence there may arise a problem in that data writing to a pixel becomes insufficient when a general driving method is employed. As a countermeasure for this problem, there is known a division driving method of dividing the screen into a plurality of display regions, and writing data into the plurality of display regions in a parallel manner. For example, Japanese Patent Application Laid-open Nos. Hei 09-258163 and Hei 10-48595 each describe a liquid crystal display device employing the division driving method of horizontally dividing the screen into two upper and lower display regions and driving the two display regions.
For example, in the division driving method of horizontally dividing the screen into two upper and lower display regions AU and AD and driving the two display regions AU and AD, the vertical scanning of sequentially selecting gate lines (scanning wiring lines) of the upper half display region AU and the vertical scanning of sequentially selecting gate lines of the lower half display region AD are performed in a parallel manner. In order to write video signals to pixel rows selected in the respective display regions AU and AD in a parallel manner, at the boundary between the regions AU and AD, source lines (video wiring lines) are each divided into a source line arranged in the region AU and a source line arranged in the region AD.